Recession probability calculator (Bayes’ rule)
Explore Bayes’ rule using your own assumed prior and signal rates. No economic forecast is supplied.
Enter a scenario
Use one currency and unit throughout. Every field is required; no market or personal financial data is loaded.
Scenario result
Fill in every field and the result appears here as you type. An empty field is missing information, not zero.
Sources and scope
Checked November 5, 2026.
Recession probability calculator (Bayes’ rule) uses the formulas shown above and assesses no personal financial circumstances.
Explore a hypothetical signal with Bayes’ rule
This sensitivity model combines your assumed prior probability with two conditional signal rates. Sensitivity describes how often the signal appears when the modeled event occurs; the false-positive rate describes how often it appears when the event does not occur. Neither rate is estimated from an economic dataset by this page.
Hypothetical example: a 10% prior, 80% sensitivity and 20% false-positive rate give a posterior of approximately 30.77% when the signal appears. The numerator is 0.10 × 0.80. The denominator adds 0.90 × 0.20 for signals without the event. The base rate therefore matters even when sensitivity looks high.
The reference explains the context of business-cycle dating, not a calibrated signal for this form. No current indicator, recession forecast or measured predictive accuracy is loaded. Change one assumption at a time to understand the formula; keep any independently researched signal and its sample period separate from the illustrative output.